Moco: convenience function to add initial/final state boundary conditions based on a states file

[carmichaelong]

Currently, setStateInfo() is used to set boundary conditions for states. This can be cumbersome in cases where, for example, you want to set the initial state based on some data. This could perhaps be done by a new function 1) that can take a states file as an argument, and then use the first row of the data, or 2) in some cases use a file already passed in (e.g., use the first row of the file passed in through setStatesReference()).

[nickbianco]

Suggested by @psbiomech.